1. Technical Field of the Invention
The present invention relates to an apparatus and a method for clocking in book blocks which are optionally spaced apart and supplied successively on a feed conveyor to a despatch conveyor provided with pushers at predetermined distances, wherein the apparatus is provided with a control unit that is connected to the feed conveyor and the despatch conveyor.
2. Prior Art
With book binding machines, it is standard practice to transport the products to be processed with the aid of a clocked transport system through the machine. During the transport, the products are moved past different processing stations and are processed therein. To insert the products into the clocked transport system, the products must be prepared so that they can, be inserted individually and at the correct point in time, meaning clocked, into the transport system.
An apparatus for regulating the supply of items to a packaging machine is known from German Patent Document DE 2346407, wherein this apparatus is provided successively arranged with a storage belt, a fast-moving belt for generating spacings, as well as a transport belt. This apparatus is suitable for clocking in items such as books and book blocks having different dimensions. The storage belt is provided with items fitting flush against each other, which are subsequently transferred to the faster-moving belt. The items are separated during this transfer, meaning they are pulled apart so that they are positioned at a distance to each other, wherein the spacing essentially corresponds to the spacing between the pushers on the following transport belt to which the items are finally transferred. Items having different lengths can be clocked in with the aid of this apparatus by running the storage belt at a higher or lower transport speed, depending on the length of the items. Methods of this type, however, are problematic when using book blocks composed of loose sheets and/or individual pages. If the book blocks are accelerated from the speed of the storage belt to the speed of the faster-moving belt, they can fall apart if the friction between the underside of the book block and the surface of the transport belt is higher than the friction between the sheets and/or the individual pages.
An apparatus for inserting items into a packaging machine is known from German Patent Document DE 29504431 U1. A roller carpet transports the items that are optionally spaced-apart to a buffer or accumulation belt on which the items are accumulated, such that they fit flush against each other. The items are subsequently transported further via a separating belt, while fitting flush against each other, are separated at the end of this separating belt, and are subsequently conveyed further with the aid of a clocking-in belt to a packaging machine. For the transfer from the separating belt to the clocking-in belt, the front edge of an item is detected with the aid of sensors, particularly photo-electric cells, at the discharge end of the separating belt. The belt drive is operated or stopped so that the items are conveyed into the gaps between the pushers on the feed belt. This apparatus is suitable for use with items having a high friction between the contact face and the separating belt, and which do not sustain damage during accelerations occurring during the start-stop operation of the separating belt. Book blocks which are composed of individual loose sheets and/or pages can fall apart based on this type of acceleration. Additionally, the orientation of the sheets or the individual pages within a book block can change impermissibly.
An apparatus for feeding individual sheets, stacked folded sheets, book blocks, books or similar items to a further processing machine is known from German Patent Document DE 202010001437 U1. With this apparatus, the items are successively transported onto a feed conveyor embodied as a first belt conveyor and provided at the downstream end with a blocking element for holding back the items or for releasing the items while synchronized with a receiving cycle. Arranged directly following the feed conveyor is a second belt conveyor which is operated at a higher speed than the first belt conveyor. The item in front is thus accelerated more when released by the blocking element than the following items, and the blocking element can be moved into the gap developing between the items. Furthermore arranged in the region of the feed conveyor is a pressure roller which rolls off the items and is provided with a reverse brake, wherein the pressure roller can prevent the transported items from bouncing back once they impact the blocking element. The pressure roller furthermore allows for a fast acceleration of the item positioned under the pressure roller, as soon as the item is released by the blocking element. During the transfer of the item from the first belt conveyor to the second belt conveyor, the acceleration of the item depends on the friction between the item and the second belt conveyor. If the friction is high, the item is strongly accelerated. In the case of a loose book block composed of sheets and/or individual pages, the danger thus exists that the book block can fall apart and/or the orientation of the sheets or the individual pages of the book block can change. With a low friction, on the other hand, it is not possible to reach high production speeds. Since the friction between the items and the second belt conveyor is determined by the material of the belt conveyor, the friction can only be changed through the arduous replacement of the material for the second belt conveyor. In addition, a great deal of time is needed to form the gaps between the items and for the stopping and releasing of the items by the blocking element.
With the apparatuses according to the prior art, it is therefore not possible to ensure a secure arrangement of sheets and/or the individual pages of the book block while maintaining the required orientation.